BuddyPress.org

Hi,
I’m using BuddyPress with the extendes profiles.
When a visitor tries to register, it may fail from time to time. After the submit, however, there is no error, but he lands directly back on the registration form – without error or anything else. But then the email address is already taken.

The question is what can be the reason that he lands again on the form after the submit and where is the email stored in the database if the registration is not completed/successful?

in wp_users I do not see anything about it

Thanks a lot!